Dissolved organic carbon (DOC) is generally defined as the organic matter that is able to pass through a filter, which removes material between 0.70 mm and 0.22 um in size. Determining the concentration of DOC in an aqueous sample, such as a sample of waste water or potable water, is important in diverse fields including pollution abatement and industrial processing situations.
Cost effective management of DOC is one of the key challenges facing today's water treatment industry. DOC has a major impact on treated water quality by for instance, acting as a food source for micro-organisms, reducing the capacity of membrane filtration by fouling, and influencing the taste and odour of water.
Techniques for the determination of DOC in an aqueous sample may involve the removal of inorganic carbon from the sample, oxidation of the organic carbon to carbon dioxide (CO2), and quantitative determination of the resulting CO2. DOC can be oxidized to CO2 by wet chemical oxidation methods (e.g. persulfate oxidation), by high temperature combustion of the liquid or dried sample in the presence of an oxidizing or surface catalyst, or photochemically by UV-irradiation, with or without the presence of an oxidizing agent. Carbon dioxide is typically quantified by infrared absorption.
Such techniques usually require a combustion step at high temperatures (of the order of 500° C.). In addition, the instrumentation required for infrared absorption for the measurement of organic carbon in water is cumbersome hence laboratory based, and/or involves sophisticated and expensive equipment. Furthermore, the sample preparation protocol is lengthy.
It would, therefore, be desirable for a relatively inexpensive compact device which provides substantially real time measurements of the content of dissolved organic carbon in water or an aqueous solution, without the requirement of high temperatures or sophisticated instrumentation.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.